Card testing is a fraudulent practice where cybercriminals use stolen or generated credit card details to determine whether the cards are valid and active. The process typically involves submitting small authorization transactions on websites or payment gateways to see if the payment is approved. Fraudsters often test cards using automated bots, rotating IP addresses, and large lists of card details, making detection challenging. Once a card is confirmed as active, it can be exploited for larger fraudulent purchases or sold on the black market. Common card testing techniques include penny testing (small charges), BIN-based testing, and manual CVV/address verification testing.
Preventing card testing is critical because it can lead to significant financial losses for businesses, cardholders, and financial institutions. Even small test transactions create costly chargebacks, impacting a business's operational costs and potentially damaging its payment processing reputation. Additionally, fraudsters who successfully validate cards can execute large-scale fraudulent purchases or perform account takeovers, further increasing the financial and reputational risk to the affected parties. This type of fraud also poses legal implications for businesses if they fail to protect sensitive financial data and their customers' security.
Beyond financial implications, unchecked card testing can severely harm consumer trust. Cardholders who see unauthorized transactions may lose confidence in the security of the merchant’s system, leading to loss of customers and damage to a brand’s reputation. Moreover, widespread card testing encourages a cycle of increasing fraud attempts, as compromised cards and successful methods are shared among criminals. Implementing robust client-side and server-side protections—including rate limiting, device fingerprinting, CAPTCHA challenges, and real-time fraud detection—is crucial to protecting customers and preventing losses at scale.
Also See: Card Testing Mitigation